1. Field of the Invention
The present invention relates to a process for optimizing the detection of the point of touching of a capacitive tactile surface.
2. Discussion of the Background
French Patent Application No. FR-A-2,732,135 (or European Patent Application EP-A-0,733,990) discloses a capacitive tactile surface taking the form of a square or rectangular glass slab covered with a conducting transparent layer (generally made of ITO, that is to say indium tin oxide), the whole being coated with an anti-reflection layer which also acts as dielectric insulant. The conducting layer is uniform and is supplied with high-frequency energy alternately at each of its corners, via a reference capacitance, the opposite corner being earthed and the other two corners being xe2x80x9cidlexe2x80x9d.
The point of touching of this known tactile surface can be determined with correct accuracy, but in certain cases of use, under unfavourable conditions (for example when the surface is misty, if the user is wearing gloves or when the surface of contact between the finger and the slab is large and/or of irregular shape, etc.), the determination of the desired point of touching may be erroneous.
The aim of the present invention is a process which makes it possible to determine with the greatest possible accuracy, for a tactile surface of the aforesaid type, the point of touching by the user, even under the most unfavourable conditions.